Delivery time: approximately 1 week

Mason Asahi continues the Mason series tradition, offering a bold reinterpretation of space, structure, and sound. At its heart is a next-generation 3D Bone Conduction System designed to enhance spatial perception without physical vibrations. Combined with twelve precisely tuned balanced armature drivers, Mason Asahi creates a listening environment that feels open, dimensional, and emotionally authentic.

UM 3D Bone Conduction System 

Our UM 3D Bone Conduction Array positions a three-axis bone conduction system along the X, Y, and Z planes, reconstructing sound like never before. The result is:

•  Realistic spatial depth
•  Improved imaging and positioning
• Vibrations you can feel across your entire skull—not just in your ears

With this three-axis layout, Mason Asahi simulates how sound travels through space, creating a sense of presence that conventional bone conduction simply cannot achieve.

Full frequency range, full-bodied sound

Mason Asahi uses three bone conduction drivers, each tuned to a specific part of the frequency range. Together, they deliver low-end power, midrange presence, and extended high-frequency detail.

• The bass is deeper and more structured.
• The mids are clearer and more expressive.
• The highs extend smoothly to 35 kHz.

This multi-axis configuration allows bone conduction to contribute across the entire range, creating a more immersive and natural presentation without changing the tonal balance or causing listening fatigue.

Twelve balanced armature drivers. Six ways. One cohesive tuning.

A total of twelve balanced armature drivers are divided across three frequency bands for optimal performance:

• 4 woofers for clear, rich bass
• 4 midrange drivers for presence and even articulation
• 4 tweeters for detailed yet controlled highs

The six-way crossover ensures each driver operates in its ideal range, delivering speed, resolution, and sonic accuracy that remain balanced at every volume.

Two systems. One seamless experience.

Mason Asahi combines air and bone conduction in one seamless 
Architecture. This dual-track approach combines soundstage and spatiality with natural reproduction through bone conduction and the precision and detail of balanced armature drivers for a comprehensive, realistic soundstage.

 The result is a more natural listening experience. Immersive, precise, and deeply engaging:

• Multiple conduction paths create subtle dynamic texture.
• The improved coupling design boosts efficiency by more than 2.3 times compared to our previous bone conduction systems.
• Spatial projection is expanded, offering enveloping width and front-to-back layering.
  

 Materials that match the craftsmanship

The Mason Asahi shell is made of rare hardwoods and high-strength carbon fiber composite. These materials are pressed into shape using precision molding, resulting in a design that is both functional and artistic. The visual finish evokes the first light of dawn. Warm golden wood grain flows into woven carbon structures, bringing organic and modern elements together in a way that feels timeless and balanced.

It looks like sound. It feels like presence.

UM Fantasy Custom cable

Each Mason Asahi comes with the UM Fantasy Custom cable. The UM Fantasy is designed to preserve the finest details and eliminate unwanted interference. It pairs well with neutral, high-resolution sources.

• 26 AWG high-purity OCC copper
• Four-core construction, each with four layers of shielding
• PVC, nylon, and FEP insulation for flexibility and durability
   

Carefully crafted leather case

The case is covered in Italian cowhide leather and lined with Indian goatskin suede.

• Exterior in UM’s signature blue
• Lined with warm, tea-brown suede, soft as morning mist
• Textured, protective, and refined to the touch

The case reflects the same qualities as the headphones it protects – durability, sophistication, and understated luxury.

Specifications

•  Drivers: 12 balanced armatures + 3 bone conduction
•  Bone conduction layout: X-, Y-, Z-triaxial array
•  Crossover: 6-way crossover
•  Impedance: 21 Ω
•  Sensitivity: 108 dB at 1 kHz
•  Frequency range: 20 Hz–35 kHz
•  Connector: 0.78 mm, 2-pin
•  Cable: UM Fantasy, 26 AWG, 4-core, multiply shielded

What’s in the box

•  Mason Asahi IEMs
•  UM Fantasy cable
•  UM3 3135C case
•  AZLA SednaEarfit Xelastec SS | MS | M
•  Silicone ear tips S | M | L
•  Cleaning cloth, cable clip, mesh pouch (2 pieces),
•  Replacement mesh filters (4 pieces), user manual, warranty card